Help! Is my EHU actually charging my batteries?

[RSD7a]

It will slip out of the black strapping, there are mounting holes on the side for a alloy bracket, why did you not cut the plug off and wire it into the main fuse box, it will work as is mind you.

Beady eyes! It won't slip out Trev. I put a support "shelf" underneath it which you can't see. It's rock solid. There are no mounting holes Trev.
The way I've wired it, it's fully removable or easily replaced without any faff.

 

[RSD7a]

I see what you mean about that thin cable you used to extend the charger leads, it does look quite thin! I'm wondering if they've sent you the correct cable.
When you stripped off the insulation from both the original and the new cables to make the join can you recall what the actual copper conductors appeared like in comparison to each other size wise?

Thanks Merl. The conductor in the "thin" one was equal to the other.

 

[trevskoda]

It won't slip out. There's a support "shelf" underneath which you can't see. It's rock solid. There are no mounting holes Trev.

See that now, but you could have used the top/bottom face screws and an angle bracket, this would leave an air gap behind it, watch you dont block the air inlet/outlet with the supporting block, do keep the locker free from stuff to avoid any overheating with poor air circulation, let us know how well its working soon.

 

[Pudsey Bear]

Beady eyes! It won't slip out Trev. I put a support "shelf" underneath it which you can't see. It's rock solid. There are no mounting holes Trev.
The way I've wired it, it's fully removable or easily replaced without any faff.

I'd have done it more or less the same but I'd have bought one designed to be mounted.

 

[Geek]

If it had been a charger etc it'd be straightforward I suppose but the control panel is wired into everything it even controls the lights which do not have their own switches, and it monitors water and battery levels too (which agree closely with my meter and the plugin displays I bought ) and I would need your type of skills to find and fit an alternative.

Generally, there is a mains input connection. Simply unplug or disconnect that, and you've effectively removed the charger from the system. That also gives you a mains input for the replacement charger!

 

[Geek]

Doesn't sound too bad until you remember that in the summertime you can get over 1kWh from a 100W panel, and I have 590W of panels connected. still only getting a 1/10th of what I would expect/hope to get in about 4 months time

Yes, you can get over 1Kw from a 100W panel, but it's unlikely. You'd need unbroken full sun all day.

In the UK you'll get an average of 5 hours of insolation in the summer, 1 hour in the winter.

So a typical summer harvest is 500Wh, not twice that.

 

[Pudsey Bear]

Much easier to just turn off the vans charger and plug mine into a van 230v socket when on EHU.

 

[Geek]

View attachment 118185
Obviously not SOC but showing that the Ctek is putting some in.

0.413 in two days is £25 per year

 

[Geek]

I remember that one Trev.
All I did was ditched the cheapo LEDs and spent a bit more (Real cheapskate me!) The second ones were really great and super efficient and had their own little driver/buck converter incorporated into each unit and their current decreased nicely when on EHU.
I've always been puzzled why the all the manufacturers of 3 way fridges show stats at 12V when in reality the supply voltage is really 14.4V as they are always powered by the alternator. Even after taking the voltage drop of the cable into consideration they all seem to sit at voltages higher than 12V and all that I've measured actually draw more current than their spec suggests and often draw currents GREATER than their recommended fuse rating.

I suspect that in a caravan, they'd only see 12v at the end of that long wire. Even on a motorhome I guess the voltage drop will be significant, though I've never measured it

 

[Geek]

Sargent's recommended diag retains the D+ input to manage compressor fridge power supply if I recall correctly.

That's a good point. I have a b2b fitted and my system doesn't use a simple SCR.

Originally I ran the fridge off the LB when driving, but that confuses the b2b so now my fridge is wired to the starter battery circuit.

The fridge is powered directly from the alternator when driving, so all the b2b output goes where it should.

The downside is that when parked up the fridge draws a small current, but it's very small. Not a problem for the starter battery.

 

[Geek]

The cables need to be at least the same or slightly bigger, and as for securing if it doesn't have mounting holes return it for one that has if possible.

The recommended approach is to keep the 12v cables as short as possible and extent the mains cable if necessary.
The 12v cables carry 20 times as much current

 

[Pudsey Bear]

0.413 in two days is £25 per year

0.413 @34p kwh ÷ 2 x 365 =

 

[Okta]

Even on a motorhome I guess the voltage drop will be significant, though I've never measured it

My voltage drop is not significant, less than 3% with the standard 16mm cabling.

 

[Pudsey Bear]

0.413 in two days is £25 per year

indeed it does, but at that point the battery wasn't up to snuff.

I have another from a few days later somewhere.

This is after 10 days + 20 hours n 27 minutes continuous so uses less as it has less to do, I reckon £10-15 pa.

And now the sun is taking over so I hopefully can wrap it up and put it away till later in the year, but I'll leave it for now ready to go.

after almost 11 days

 

[merl]

Beady eyes! It won't slip out Trev. I put a support "shelf" underneath it which you can't see. It's rock solid. There are no mounting holes Trev.
The way I've wired it, it's fully removable or easily replaced without any faff.

From the sales pics it seems they sometimes come with mounting holes and sometimes not. I think the perforated strapping is a nice idea because if it resonates too much through the furniture when the fan kicks in you can trap some rubber underlay between the charger and back board and thin strip between charger and strap so the whole thing floats.